A Molecular Switch for Neuroprotective Astrocyte Reactivity
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ABSTRACT:
ORGANISM(S): Mus musculus
PROVIDER: GSE237675 | GEO | 2023/12/11
REPOSITORIES: GEO
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Project description:The intrinsic mechanisms that regulate neurotoxic versus neuroprotective astrocyte phenotypes and their effects on central nervous system (CNS) degeneration and repair remain poorly understood. Here, we show injured white matter astrocytes differentiate into two distinct C3-positive and C3-negative reactive populations, previously simplified as neurotoxic (A1) and neuroprotective (A2)1,2, which can be further subdivided into unique subpopulations defined by proliferation and differential gene expression signatures. We find the balance of neurotoxic versus neuroprotective astrocytes is regulated by discrete pools of compartmented cAMP derived from soluble adenylyl cyclase (sAC) and show proliferating neuroprotective astrocytes inhibit microglial activation and downstream neurotoxic astrocyte differentiation to promote retinal ganglion cell (RGC) survival. Finally, we report a new, therapeutically tractable viral vector to specifically target optic nerve head astrocytes and show elevating nuclear or depleting cytoplasmic cAMP in reactive astrocytes inhibits deleterious immune cell infiltration and promotes RGC survival after optic nerve injury. Thus, soluble adenylyl cyclase and compartmented, nuclear- and cytoplasmic-localized cAMP in reactive astrocytes act as a molecular switch for neuroprotective astrocyte reactivity that can be targeted to inhibit microglial activation and neurotoxic astrocyte differentiation to therapeutic effect. These data expand upon and define new reactive astrocyte subtypes and represents a novel step towards the development of gliotherapeutics for the treatment of glaucoma and other optic neuropathies.
2023-12-11 | GSE245816 | GEO
Project description:This SuperSeries is composed of the SubSeries listed below. Disease, injury, and aging induce pathological reactive astrocyte states that contribute to neurodegeneration. Modulating reactive astrocytes therefore represents an attractive therapeutic strategy. Here, we describe the development of an astrocyte phenotypic screening platform for identifying chemical modulators of astrocyte reactivity. Leveraging this platform for chemical screening, we identify HDAC3 inhibitors as effective suppressors of pathological astrocyte reactivity. We demonstrate that HDAC3 inhibition reduces molecular and functional characteristics of reactive astrocytes in vitro. Transcriptional and chromatin mapping studies show that HDAC3 inhibition disarms pathological astrocyte gene expression and function while promoting the expression of genes associated with beneficial astrocytes. Administration of RGFP966, a small molecule HDAC3 inhibitor, blocks reactive astrocyte formation and promotes neuroprotection in vivo in mice. Collectively, these results establish a platform for discovering modulators of reactive astrocyte states, inform the mechanisms that control astrocyte reactivity, and demonstrate the therapeutic benefits of modulating astrocyte reactivity for neurodegenerative diseases.
2024-01-10 | GSE185215 | GEO
Project description:Disease, injury, and aging induce pathological reactive astrocyte states that contribute to neurodegeneration. Modulating reactive astrocytes therefore represents an attractive therapeutic strategy. Here, we describe the development of an astrocyte phenotypic screening platform for identifying chemical modulators of astrocyte reactivity. Leveraging this platform for chemical screening, we identify HDAC3 inhibitors as effective suppressors of pathological astrocyte reactivity. We demonstrate that HDAC3 inhibition reduces molecular and functional characteristics of reactive astrocytes in vitro. Transcriptional and chromatin mapping studies show that HDAC3 inhibition disarms pathological astrocyte gene expression and function while promoting the expression of genes associated with beneficial astrocytes. Administration of RGFP966, a small molecule HDAC3 inhibitor, blocks reactive astrocyte formation and promotes neuroprotection in vivo in mice. Collectively, these results establish a platform for discovering modulators of reactive astrocyte states, inform the mechanisms that control astrocyte reactivity, and demonstrate the therapeutic benefits of modulating astrocyte reactivity for neurodegenerative diseases.
2024-01-10 | GSE230817 | GEO
Project description:Disease, injury, and aging induce pathological reactive astrocyte states that contribute to neurodegeneration. Modulating reactive astrocytes therefore represents an attractive therapeutic strategy. Here, we describe the development of an astrocyte phenotypic screening platform for identifying chemical modulators of astrocyte reactivity. Leveraging this platform for chemical screening, we identify HDAC3 inhibitors as effective suppressors of pathological astrocyte reactivity. We demonstrate that HDAC3 inhibition reduces molecular and functional characteristics of reactive astrocytes in vitro. Transcriptional and chromatin mapping studies show that HDAC3 inhibition disarms pathological astrocyte gene expression and function while promoting the expression of genes associated with beneficial astrocytes. Administration of RGFP966, a small molecule HDAC3 inhibitor, blocks reactive astrocyte formation and promotes neuroprotection in vivo in mice. Collectively, these results establish a platform for discovering modulators of reactive astrocyte states, inform the mechanisms that control astrocyte reactivity, and demonstrate the therapeutic benefits of modulating astrocyte reactivity for neurodegenerative diseases.
2024-01-10 | GSE184437 | GEO
Project description:Disease, injury, and aging induce pathological reactive astrocyte states that contribute to neurodegeneration. Modulating reactive astrocytes therefore represents an attractive therapeutic strategy. Here, we describe the development of an astrocyte phenotypic screening platform for identifying chemical modulators of astrocyte reactivity. Leveraging this platform for chemical screening, we identify HDAC3 inhibitors as effective suppressors of pathological astrocyte reactivity. We demonstrate that HDAC3 inhibition reduces molecular and functional characteristics of reactive astrocytes in vitro. Transcriptional and chromatin mapping studies show that HDAC3 inhibition disarms pathological astrocyte gene expression and function while promoting the expression of genes associated with beneficial astrocytes. Administration of RGFP966, a small molecule HDAC3 inhibitor, blocks reactive astrocyte formation and promotes neuroprotection in vivo in mice. Collectively, these results establish a platform for discovering modulators of reactive astrocyte states, inform the mechanisms that control astrocyte reactivity, and demonstrate the therapeutic benefits of modulating astrocyte reactivity for neurodegenerative diseases.
2024-01-10 | GSE185605 | GEO
Project description:Disease, injury, and aging induce pathological reactive astrocyte states that contribute to neurodegeneration. Modulating reactive astrocytes therefore represents an attractive therapeutic strategy. Here, we describe the development of an astrocyte phenotypic screening platform for identifying chemical modulators of astrocyte reactivity. Leveraging this platform for chemical screening, we identify HDAC3 inhibitors as effective suppressors of pathological astrocyte reactivity. We demonstrate that HDAC3 inhibition reduces molecular and functional characteristics of reactive astrocytes in vitro. Transcriptional and chromatin mapping studies show that HDAC3 inhibition disarms pathological astrocyte gene expression and function while promoting the expression of genes associated with beneficial astrocytes. Administration of RGFP966, a small molecule HDAC3 inhibitor, blocks reactive astrocyte formation and promotes neuroprotection in vivo in mice. Collectively, these results establish a platform for discovering modulators of reactive astrocyte states, inform the mechanisms that control astrocyte reactivity, and demonstrate the therapeutic benefits of modulating astrocyte reactivity for neurodegenerative diseases.
2024-01-10 | GSE185212 | GEO
Project description:Disease, injury, and aging induce pathological reactive astrocyte states that contribute to neurodegeneration. Modulating reactive astrocytes therefore represents an attractive therapeutic strategy. Here, we describe the development of an astrocyte phenotypic screening platform for identifying chemical modulators of astrocyte reactivity. Leveraging this platform for chemical screening, we identify HDAC3 inhibitors as effective suppressors of pathological astrocyte reactivity. We demonstrate that HDAC3 inhibition reduces molecular and functional characteristics of reactive astrocytes in vitro. Transcriptional and chromatin mapping studies show that HDAC3 inhibition disarms pathological astrocyte gene expression and function while promoting the expression of genes associated with beneficial astrocytes. Administration of RGFP966, a small molecule HDAC3 inhibitor, blocks reactive astrocyte formation and promotes neuroprotection in vivo in mice. Collectively, these results establish a platform for discovering modulators of reactive astrocyte states, inform the mechanisms that control astrocyte reactivity, and demonstrate the therapeutic benefits of modulating astrocyte reactivity for neurodegenerative diseases.
2024-01-10 | GSE231598 | GEO
Project description:Neuroinflammation is a common feature of neurodegenerative disorders such as Alzheimer's disease (AD). Neuroinflammation is induced by dysregulated glial activation, and astrocytes, the most abundant glial cells, become reactive upon neuroinflammatory cytokines released from microglia, and actively contribute to neuronal loss. Therefore, blocking reactive astrocyte functions is a viable strategy to manage neurodegenerative disorders. However, factors or therapeutics directly regulating astrocyte subtype remain unexplored. Here, we identified transcription factor NF-E2-related factor 2 (Nrf2) as a therapeutic target in neurotoxic reactive astrocytes upon neuroinflammation. We found that the absence of Nrf2 promoted the activation of reactive astrocytes in the brain tissue samples obtained from AD model 5xFAD mice, whereas enhanced Nrf2 expression blocked the induction of reactive astrocyte gene expression by counteracting NF-kB subunit p65 recruitment. Neuroinflammatory astrocytes robustly upregulated genes associated with type I interferon and the antigen-presenting pathway, which were suppressed by Nrf2 pathway activation. Moreover, impaired cognitive behaviors observed in AD mice were rescued upon ALGERNON2 treatment, which potentiated Nrf2 pathway and reduced the induction of neurotoxic reactive astrocytes. Thus, we highlight the potential of astrocyte-targeting therapy by promoting the Nrf2 pathway signaling for neuroinflammation-triggered neurodegeneration.
2023-08-07 | GSE237423 | GEO
Project description:Neuroinflammation is a common feature of neurodegenerative disorders such as Alzheimer's disease (AD). Neuroinflammation is induced by dysregulated glial activation, and astrocytes, the most abundant glial cells, become reactive upon neuroinflammatory cytokines released from microglia, and actively contribute to neuronal loss. Therefore, blocking reactive astrocyte functions is a viable strategy to manage neurodegenerative disorders. However, factors or therapeutics directly regulating astrocyte subtype remain unexplored. Here, we identified transcription factor NF-E2-related factor 2 (Nrf2) as a therapeutic target in neurotoxic reactive astrocytes upon neuroinflammation. We found that the absence of Nrf2 promoted the activation of reactive astrocytes in the brain tissue samples obtained from AD model 5xFAD mice, whereas enhanced Nrf2 expression blocked the induction of reactive astrocyte gene expression by counteracting NF-kB subunit p65 recruitment. Neuroinflammatory astrocytes robustly upregulated genes associated with type I interferon and the antigen-presenting pathway, which were suppressed by Nrf2 pathway activation. Moreover, impaired cognitive behaviors observed in AD mice were rescued upon ALGERNON2 treatment, which potentiated Nrf2 pathway and reduced the induction of neurotoxic reactive astrocytes. Thus, we highlight the potential of astrocyte-targeting therapy by promoting the Nrf2 pathway signaling for neuroinflammation-triggered neurodegeneration.
2023-08-07 | GSE237422 | GEO
Project description:Glaucoma leads to vision loss due to retinal ganglion cell death. Astrocyte reactivity contributes to neurodegeneration. Our recent study found that lipoxin B4 (LXB4), produced by retinal astrocytes, has direct neuroprotective actions on retinal ganglion cells. In this study, we aimed to investigate how the autacoid LXB4 influences astrocyte reactivity in the retina under inflammatory cytokine-induced activation and ocular hypertension conditions. The protective activity of LXB4 was investigatedin vivousing the mouse silicone-oil model of chronic ocular hypertension (n=40). By employing a range of analytical techniques, including bulk RNA-seq, RNAscope in-situhybridization, qPCR, and lipidomic analyses, we discovered the formation of neuroprotective lipoxins in rodents (including the retina and optic nerve), primates (optic nerve), and human brain astrocytes, indicating their presence across various species. Our findings in the mouse retina demonstrated significant dysregulation of the lipoxin pathway in response to chronic ocular hypertension, leading to an increase in 5-lipoxygenase (5-LOX) activity and a decrease in 15-lipoxygenase activity. This dysregulation was coincident with a marked upregulation of astrocyte reactivity. Reactive human brain astrocytes also showed a significant increase in 5-LOX. Administration of LXB4 regulated the lipoxin pathway, restored and amplified LXA4 generation (another lipoxin with distinct bioactions), and mitigated astrocyte reactivity in mouse retinas and human brain astrocytes. In conclusion, the lipoxin pathway is functionally expressed in rodents, primates, and human astrocytes, and is a resident neuroprotective pathway that is downregulated in reactive astrocytes. Novel cellular targets for LXB4’s neuroprotective action are inhibition of astrocyte reactivity and restoration of lipoxin generation. Amplifying the lipoxin pathway is a potential target to disrupt or prevent astrocyte reactivity in neurodegenerative diseases.
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